Morphological variations in oidium formation in the basidiomycete Coprinuscinereus

Oidiophores with uninucleate oidia are produced on the aerial mycelium of C oprinus cinereus and occasionally also on the submerged mycelium. Oidiophor e development starts with the formation of a stem cell and proceeds with st em cell elongation, followed by the formation of oidial hyphae at the tip o f the stem cell and subsequent release of matured oidia. However, analysis of more than 20 different C, cinereus strains revealed that oidiophore form ation is a flexible process. Based on morphological variations, we defined four main types of oidiophores. Types I and 2 oidiophores produced oidia at the tip(s) of simple (type I) or branched stems (type 2). Types 3 and 4 oi diophores were characterized by the absence of stem cell elongation (type 3 ) or stem cell formation (type 4). All strains examined produced types I an d 2 oidiophores and some produced also types 3 and 4 oidiophores but the fr equency of the different oidiophore types varied strongly from strain to st rain.